Poly(vinylchloride) has been reacted with dosium azide with the introduction of azide groups into the polymeric chain. See, M. Takeishi et al., Polymer Letters, 7201 (1969), and H. L. Cohen, Jour. Polymer Science 19, 3269, (1981). However, the product, produced in accordance with the teachings of these references contained 20 to 40 percent of the chlorine originally in the polymeric reactant and this rendered the product, i.e., poly(vinylazide) unacceptable for use in propellant and explosive formulations. The use of poly(vinylazide) of the cited art is accompanied by a high degree of corrosion of the bore of a weapon from which it is fired, and also such energetic polymer produces the formation of a plume which indicates the position of the weapon from which it is fired. The latter telltale plume is produced by the reaction of the HLl present in the formulation with atmospheric moisture.
Surprisingly, we have found that the amount of chlorine in the reaction product of poly(vinylchloride) and sodium azide may be drastically reduced by heating the gel produced in the presence of a metallic azide for an extended period of time. The final product, poly(vinylazide), was found to be highly energetic as indicated by a positive match test.